Support units especially for mine roof



May v18, 1965 M. MERIAUX ETAL SUPPORT UNITS ESPECIALLY FOR MINE ROOF Filed March 18, 1963 3 Sheets-Sheet 1 l l i l l l l l l l l l l l l l l l l l l l l l (lb fa May 18, 1965 M. MERIAUX ETAL SUPPORT UNITS ESPECIALLY FOR MINE ROOF 5 Sheets-Sheet 2 Filed March 18, 1963 M1. MER-mmm Erp-h SUPPORT UNITES ESPE'C/I-I'IIW FOR? MINE HUGE May 1'8 1965Z Filed March 18, 196s Y mmv. nllllllllll @A W 4 United States Patent O 3 184 206 SUPPORT UNITS ESPECIALLY FR MINE ROGF Michel Meriaux and Michel Lablache Combier, Witte!- sheim, France, assignors to Mines Donianiales de Potasse dAlsace, Mulhouse, Haut-Rhin, France, a French society Filed Mar. 18, 1963, Ser. No. 265,706 Claims priority, application France, Mar. 20, 1962, 891,572, Patent 1,325,740 Claims. (Cl. 24S- 357) I-t is known that walking support members generally comprise a number of hydraulic pit props borne by a base frame of varying size and compactness, formed, for example, by a high rigid sheet-metal box, which gives the whole unit great stability and holds the pit props in place very efficiently. It has, however, been found necessary to leave a clearance between each prop and the top of the base frame and to insert a resilient element to protect the prop, eg., a spring or more simply a rubber shock absorber such as a ring or collar. This arrangement prevents the props from bearing against the frame and being damaged by considerable transverse forces, particularly in sloping strata. The devices also recenter the prop when it is released for the support to be moved forward.

If roof subsidence is likely to be appreciable, however, the prop must be given suiiicient freedom after locking. Under these conditions, an impossible situation is very soon reached; very thick rubber is necessary to give a clearance of several tens of millimetres. The resistance offered by the rubber very quickly increases with crushing, the bending strength of the prop is very soon exceeded and it comes into engagement with the frame.

If, on the other hand, a very soft rubber is used whose resistance remains less than the prop bending strength after several tens of millimetres crushing, ,there is a risk of not producing sufficient force to compensate for the prop weight and recenter it when the unit is released. It is, in fact, of the greatest importance that the necessary clearance should be guaranteed, and this means that when the props are pressurised they must have been restored to the mean position. This condition is not fulfilled if the rubber is systematically compressed in a particular direction during the movement of a unit.

The subject of the invention is a centering device, more particularly for the centering of support props, particularly walking supports, which obviates the aforementioned disadvantages and more particularly fullls the following two conditions: iirstly, centering of the props in their base frame when they are released, i.e., before the movement of the support, and secondly, sufficient clearance between the props and the top of the frame, so that the props are protected from abnormal bending forces if the roof subsides, more particularly in very sloping strata.

Such a centering device can be used of course-without going beyond the scope of the invention-for straightening or centering in relation to a transverse support member a horizontal, vertical or inclined element which may depart from its initial axial position during operation.

According to a first feature yof the invention, the resilient element disposed between a member, e.g., a prop of a support unit, and its transverse supporting element, is formed by a sealing-tight deformable chamber comprising at least one aperture which can be connected to a duct for fluid of controllable pressure. rlille duct can, for instance, be connected to a pump and thus be under pressure when the pump is working and be brought to the pump reservoir pressure when the pump is not operating. Similarly, without going beyond the scope of the invention, the aperture in the sealing-tight chamber could be connected selectively to a duct for tiuid under Cice pressure, e.g., a duct communicating with a pressure accumulator, and to an outlet duct for the fluid. The deformable chamber will preferably be substantially toroidal and be disposed between suitably shaped elements borne by the member and its transverse support element respectively.

According to a preferred feature of the invention the cross-section of the sealing-tight chamber is bean-shaped and comprises two parts of opposite concavity disposed inside one another. These two parts are respectively supported on parts of corresponding shape unitary with the member and its transverse support element, the supporting zone for the inner part being disposed in the free state near the centre of the outer part.

Because of this arrangement, as will be shown hereinafter, Ithe force transmitted to the member by the chamber when it is pressurised is substantially independent of the deformation previously undergone by the chamber. Under these conditions the maximum force will always be available to restore the prop member to its initial axial position irrespective of its displacement, more particularly when the props are inclined when they'are to be advanced.

The invention will be more readily understood and various advantages and subsidiary characteristics will be apparent from the following description of an advantageous embodiment given by Way of example with reference to the accompanying drawings wherein:

FIGURE l is an elevation of a walking support unit whose props are provided with the device according to the invention;

FIGURE la is a partial view similar to FIGURE l showing another embodiment of the invention;

FIGURE 2 is a section through an advantageous embodiment of the resilient element disposed between a prop and its transverse support element;

FIGURE 2a is a similar view to FIGURE 2 after the prop has been inclined;

FIGURE 3 is a similar view to FIGURE 2 of another embodiment; and

FIGURE 4 is a similar view to FIGURE 2 of another embodiment.

FIGURE l shows a walking support unit comprising in known manner a base box 1 whose bottom surface '1a supports a number of props 2 resting pivotally thereon. AS shown in the drawing, such unit will generally comprise a number of props retained by appropriate transverse support elements disposed a certain height above the base of the unit; if the base element is a rigid box the props pass through the top surface 1b of such box through appropriate apertures 1c to this end.

ln all instances the props rnust be able to become inclined in `relation to the base surface 1a, more particularly when roof subsidences take place in very sloping strata. Each aperture 1c or 4the appropriate prop retaining parts must therefore leave a certain clearance around the latter, `so that their inside diameter must be greater than the outside diameter of the prop.

On the edge of each aperture 1c and on the outer surface of the corresponding propl two appropriately shaped parts 3 and 4 are attached with a resilient and sealing-tight chamber 5 .between them, which is supported laterally in recesses in each of the parts 3 and 4. In FIGURE l the chamber 5 is toroidal in shape and comprises an aperture 5a -to which a duct 6 is attached. The duct is itself connected to a conduit 7 feeding all or some of the props forming the various units. The conduit 7 can lbe put into communication with a hydraulic or pneumatic pressure iiuid source, e.g., a pump or a pressure accumulator.`

The device operates as follows: the props 2 are iirst locked between the mine roof and the base 1d of the box resting ou the floor; when roof subsidences have caused the props to become inclined to the position shown in chain lines in FIGURE 1, the Iconduit 7 is connected t-o Ilthe hydraulic or pneumatic pressure source, eg., Vby starting the aforementioned pump. The props are then. lowered by reducing the hydraulic pressure inside their cylinder. The ination of the .chambers centers the props while in their lowered positions in relation to the base box. The unit or units are then moved in known manner, whereafter the props 2 .are raised, while the pressure in the chamber 5 is maintained. When the props are iirmly engaged between the floor .andl the roof the pressure in the conduit 7 is reduced .to zero, e.g., by stopping the pump. Under these conditions the props may possibly again become inclined by transverse forces of various kinds, more particularly, roof subsidences, rwithout encountering parasitic resistances which might cause abnormal bending stresseson Ithe props. This shows .the importance of the improvements to walking supports by lthe present'invention and also their simplicity and inner periphery 3a of the plate y3d is near the center of the cross-section of the annular groove'in the part 4. When the prop 2 is inclined in relation to t-he base box, .the part 4 will move towards or away from the annular plate 3d, i.e.,l the inner periphery 3a of the Iannular plate -3d'fwill :be moved in relation to the part 4 over a distance X in FIGURE 2. The distance X corresponds on the' one band to the clearance necessary to absorb roof subsidences, .and -onthe other to .the deformation of the chamber 5 during which it may be considered that the force transmitted by said chamber to the part 4, i.e., the torce of the part 5b of the chamber on .the inner Iperiphery Y 3a of .the annular plate 3d remains substantially constant.

base frame (FIGURE 2a) the inner part 5b which is normally supported on the inn-er periphery 3a of the plate i 3d has left such periphery in the opposite zone to the ease of operation. The method of operation just described could, of course, be modified, according .to the particular conditions-in which the centring device is used.

FIGURE 1 shows a single sealing-tight chamber formed by a torus, but clearly other embodiments could be envisaged Vwithout going outside the V.scope of the invention. For instance, similar chambersto lthat shown in FIGURE 1 could be superimposed on top of one another,

or the chambers could be replaced by a single flexible Y times around the prop` 2 (FIG- undergo bending stresses during inclination, and this would l inclination. When the inside of the chamber 5 is pressurized, the part 5b disposed in the opposite zone to the inclination rst of all tends to become deformed and to resume an equilibrium shape, i,e., the circular shape shown in chain lines in the ligure. 'Ilhis may cause some delay in the recentering of the prop and risk of damage in the chamber 5.V V

To obviatenthis disadvantage, accordingto the invention means are lprovided to prevent the inner part 5b from becoming displaced beyondits initial position close to Ythe center ot the outer part 5a. To this end flexible but f inextensible elements are used whichconnect the inner part necessitate reinforcement of their structure, or a reduced Y,

a sealing-tight chamber whichgcan be inflated if lrequired or subjected to initial inside pressure, but which is of a shape such as to exert on the Vprop .to be recentered a force substantially independent of the axial olf-setting of the prop in relation to its transverse supporting element.

The crushing force curve' has been experimentally de-Y termined andlcalculated for a chamber inflated with air or Y water in relation to the movement of an element supported on the inner or outer periphery of such chamber. It

was round that the crushing rforce passes through a maxi-4 5b to thefrecess for the outer ,part 5a. As shown in FIG- center of the part 5b, passes'through the part 5a, and is xed .on the element 4 by any appropriate means. In place of metal braids a flexible diaphragm 8a could be placed in the chamber 5 duringy manufacture, such diaphragrnfhaving means Sb lfor vfixing in -the element 4 unitary with the prop on the outside of the part 5a (FIG- URE'4). I

According to the'embodiment shown'in FIGURE 3, the center of the part 5a can bey cut out.v In that case the chamber 5 is fixed in the element 4 in a lmanner similar to a tire without an inner t-ube,'and the two free ends of the Vpart 5a will preferably be reinforced'by metal rings 9 or the like. This arrangement'makes it very easy to tix metal bra-id in the element 4. kIn this embodiment two series of braids y8 are provided and are inclined in relation to the equatorial plane of the chamber 5.

when the movement of the part supported on the y periphery is close lto the radius of the :chamber section;

In that case, the crushing forceis substantially equal to chamber 5 of the device described above is for the cross-V section of such ychamber to be bean-shaped'as shown in- FIGURE 2.V Y l It can be seen ffrom the drawingthat'the'cross-sectiony Y of the chamber k5 comprises two parts 5a and'Sb 4of oppo-fl site concavity to one another,` and the part 5b is disposed inside the part.k 5a which 4is itself sernicircular. v rtree state, ie., when there is no pressure inside the chamber, :the part 5b extends almostto Vthe centerA of the part In the` 5a. The part 4 -ixedr'on the ,shaft of the prop 2 has an Y outwardly open annular groovey which strictly'matches the' shape ott the par-t 5a fof the Ychamber 5.1 i

. VThe supportingpart 3 unitary with the .topisurpfaoe ,1b-ii of the base box .comprises angannular plate r3dr,cooperating :with the] inner1p`art5bV of the chamber 5. It should` be `noted thatV when: .thefprop is properlycentered;'thev V when used on amine supportunit. To this end, prolongationgkta A(FIGURE 2)areprovided yfon the edgesY It is clear that the number and arrangement of the bra-ids, Vdiaphragm or the like, arenot limited to the above,

but can be determined in relation to the particular conditions of use and also assembly requirements. It should be emphasized that in the embodiment shown in FIGURE 3, the braids or diaphragm-s 8 can be xed directly on the Y braces 9 of the part'Sa whichV are themselves substantially fixedin relation to thepiece 4. The positions of the inner and outer parts of the bean-shapecould beinverted without going outside the scope of the invention.

Yeither ot such parts could be.associated'with the movable membenfor l'withits,transverse V,supporting element, as

Similarly,

circumstances require.

Finally, it is clear thatfthe total dimensions, more` particularly the diameter of the cross-section of thebean shape Vshould be determined accordingly irstly to the Vforces necessary to,y recenter the'prop, and secondly the necessary clearance corresponding "to the movement of the prop'rin relation to its transverse supporting element.v It should beemphasized thatV since the chamber S is a relativelyfragile'device it should have azprotect-ive casing of the annular :groovein thexelement 4, suchv prolongationsengaging slidably between the top andfbottom suryfraceslib-and'3c of anV annular casingunitary with the annular plate 3d. The two surfaces 3b and 3c are disposed on either side of the annular plate and the distance of the prolongations 4a of the supporting element 4 from the bottom of the casing is enough to allow the prop to be moved over a distance X in relation to the base box.

It is clear that the various embodiments described above are only advantageous examples of embodiments of the invention, which covers all variants. The engineer in the art will realize that Ithe device according to the invention can be used in numerous cases, but the present case should again be emphasized, viz. shift jacks for walking support units in mines, which will advantageously be provided with a device according to the invention.

What we claim is:

1. A support unit comprising ya support element, a support structure defining an aperture which receives the support element, the support element being movable within the aperture relative to the support structure, a sealingtight resilient deformable chamber located between the rim of said aperture and said support element and means for coupling the interior of said chamber with a source of uid pressure to recenter said support element relative to said aperture after displacement of said element from a co-axial position relative to said aperture.

2. A support unit according to claim 1 in which the chamber is of toroidal shape.

3. A support unit according to claim 1 in which the chamber comprises a flexible conduit coiled in a plurality of turns about said support element.

4. A support unit comprising a support element, a support structure deining an aperture which receives said support element, a seal-tight lresilient deformable chamber which in cross-section includes opposite concave walls facing in like direction, one of said walls lying within the limits of the other, and a pair of support members respectively carried by said element and said structure and of shape corresponding to the exterior of said walls, in the rest state said walls engaging said members, said element being co-axial with said aperture and the innermost part of said inner wall being adjacent the center of said outer Wall, means being provided to couple said chamber to a source of fluid pressure to recenter the element relative to said support structure after displacement of said element relative to said aperture.

5. A support unit according to claim 4 including anchoring means secured to said inner wall and to means static relative to said outer Wall to limit displacement of the innermost part of said inner wall away from said outer Wall.

6. A support unit according to claim 5 including anchoring means between said inner Wall and means static relative to said outer wall, said anchoring means comprising metal braiding.

7. A support unit according to claim 5 including anchoring means bet-Ween said inner wall and means static relative to said outer wall, sa-id anchoring means comprislng a diaphragm.

8. A mine roof support unit comprising a hase frame, a plurality of telescopic props pivotally supported by said frame, a support structure fast with said frame and deining apertures each receiving and llimiting pivotal movement of one of said props, a resi-lient deformable sealtight chamber supported by the rim of each aperture, each of said chambers including oposite walls which are concave and like facing, one lying within the other, said inner wal-l being concave on the exterior and engaging the rim of said aperture and said outer wall being concave on the interior and seating against a concave element carried by said prop means being provided for coupling the interior of each of said chambers with a uid pressure source.

9. A support unit according to claim 8 including a pair of spaced guide surfaces on said structure in respect of each aperture, said surfaces slidably receiving said concave element of said prop received by said aperture.

10. A support unit comprising a support element, a support structure defining an aperture which receives said support element, a seal-tight resilient deformable chamber which in cross-section includes :opposite concave walls lfacing in like direction, one of said walls lying within the limits of the other, and a pair of support members respectively carried by said element and said structure of shape corresponding to the exterior of said walls, and the sup'- port member in respect of the outer wall forming ia part of that wall, in the rest state said walls engaging said members, said element being `co-axial with said aperture, and the innermost part of said inner wall being adjacent the center of said outer wall, means being provided to couple said chamber to a source of Huid pressure to recenter the element relative to said support structure after displacement of said element relative to said aperture.

References Cited bythe Examiner UNITED STATES PATENTS 2,985,419 5/61 Duncan 248--361 FOREIGN PATENTS 1,070,311 2/54 France.

1,034,568 7/58` Germany.

CLAUDE A. LE ROY, Primary Examiner, 

1. A SUPPORT UNIT COMPRISING A SUPPORT ELEMENT, A SUPPORT STRUCTURE DEFINING AN APERTURE WHICH RECEIVES THE SUPPORT ELEMENT, THE SUPPORT ELEMENT BEING MOVABLE WITHIN THE APERTURE RELATIVE TO THE SUPPORT STRUCTURE, A SEALINGTIGHT RESILIENT DEFORMABLE CHAMBER LOCATED BETWEEN THE RIM OF SAID APERTURE AND SAID SUPPORT ELEMENT AND MEANS FOR COUPLING THE INTERIOR OF SAID CHAMBER WITH A SOURCE OF FLUID PRESSURE TO RECENTER SAID SUPPORT ELEMENT RELATIVE TO SAID APERTURE AFTER DISPLACEMENT OF SAID ELEMENT FROM A CO-AXIAL POSITION RELATIVE TO SAID APERTURE. 